Field of the Invention
The present invention relates to a heat pump system for a vehicle. More particularly, the present invention relates to a heat pump system for a vehicle capable of cooling and heating an interior of the vehicle selectively using a high-temperature coolant and a low-temperature coolant.
Description of Related Art
Generally, an air conditioner for a vehicle includes an air conditioner device circulating a refrigerant in order to heat or cool an interior of the vehicle.
The air conditioner device, which is to maintain the interior of the vehicle at an appropriate temperature regardless of a change in an external temperature to maintain a comfortable interior environment, is configured to heat or cool the interior of the vehicle by heat exchange by an evaporator in a process in which a refrigerant discharged by driving of a compressor is circulated to the compressor through a condenser, a receiver drier, an expansion valve, and the evaporator.
That is, the air conditioner device lowers a temperature and a humidity of the interior by condensing a high-temperature high-pressure gas-phase refrigerant compressed from the compressor by the condenser, passing the refrigerant through the receiver drier and the expansion valve, and then evaporating the refrigerant in the evaporator in a cooling mode in summer.
Meanwhile, recently, in accordance with a continuous increase in an interest in energy efficiency and an environmental pollution problem, the development of an environmentally-friendly vehicle capable of substantially substituting for an internal combustion engine vehicle has been demanded, and the environmentally-friendly vehicle is generally classified into an electric vehicle driven using an fuel cell or electricity as a power source and a hybrid vehicle driven using an engine and a battery.
In the electric vehicle or the hybrid vehicle among these environmentally-friendly vehicles, a separate heater is not used unlike an air conditioner of a general vehicle, and an air conditioner used in the environmentally-friendly vehicle is generally called a heat pump system.
Meanwhile, the electric vehicle generates driving force by converting chemical reaction energy between oxygen and hydrogen into electric energy. In this process, heat energy is generated by a chemical reaction in a fuel cell. Therefore, it is necessary in securing performance of the fuel cell to effectively remove generated heat.
In addition, the hybrid vehicle generates driving force by driving a motor using electricity supplied from the fuel cell described above or an electrical battery, together with an engine operated by a general fuel. Therefore, heat generated from the fuel cell or the battery and the motor should be effectively removed in order to secure performance of the motor.
Therefore, in the hybrid vehicle or the electric vehicle according to the related art, a cooling device, a heat pump system, and a battery cooling system should be configured using separate closed circuits, respectively, so as to prevent heat generation of the motor, an electric component, and the battery including the fuel cells.
Therefore, a size and a weight of a cooling module disposed at the front of the vehicle are increased, and a layout of connection pipes supplying a refrigerant or a coolant to each of the heat pump system, the cooling device, and the battery cooling system in an engine compartment becomes complicated.
In addition, since the battery cooling system warming up or cooling the battery depending on a state of the vehicle is separately provided so that the battery exhibits optimal performance, a plurality of valves for connecting the respective connection pipes to each other are used, and noise and vibrations due to frequent opening or closing operations of these valves are transferred to the interior of the vehicle, such that a ride comfort deteriorates.
The information disclosed in this Background of the Invention section is only for enhancement of understanding of the general background of the invention and may not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person skilled in the art.